The Oil Beetles of Eliza Howell Park

I see Oil Beetles — large, dark, metallic-looking beetles – in Eliza Howell Park only in October and November. They are not particularly photogenic or otherwise likely to catch someone’s attention, but their story is part of the fascinating natural world that exists right here in the neighborhood.

I last saw one in 2019 on November 25, as it and I were walking on the park road.

Oil Beetles, a type of Blister Beetle, are nearly an inch long and, when I see them, are walking slowly on the ground in or near the fields in the park. My earliest 2019 observation was on October 17 (next picture). They are not numerous; even in their “season” I do not see them on every visit.

Oil Beetles are flightless. The adults emerge in the Fall and proceed in their slow and somewhat cumbersome walk toward a good place to winter in the soil. Based on the published research I have consulted, I think the female lays eggs in the spring, but I have seen them mating in the Fall. This pair was photographed in early November.

They are called “Oil” Beetles because, like other Blister Beetles, they can secrete oily droplets from their leg joints when threatened. This “oil” contains a toxic chemical (cantharidin) that can cause painful blisters on human skin.

They have no hind wings and the short front wings cover only a small part of the large abdomen.

Some Oil Beetles spend the immature phases of life in parasitic fashion in the nests of ground-nesting bees, eating the food that is brought in for bee larvae. 

There is much I don’t know about these beetles, but they now have my attention. I am sure that I will think of Oil Beetles when I next see ground-nesting bees.

 

The River, the Season, the Weather: Tracking Fall 2019

I often stop on the footbridge during my walks in Eliza Howell Park, stop and take a picture, looking upstream the Main branch of the Rouge River. These pictures help me track seasonal changes and fluctuations in water level.

Below are 8 photos taken on different days during the four weeks from October 16 to November 13, 2019. Some from sunny days and some from cloudy days, these pictures presdent the progress of Fall this year.

October 16, 2019  (9:47 a.m.   Approximately 50 degrees F)

October 20, 2019 (3:04 p.m.   Approximately 60 degrees F)

October 24, 2019  (11:23 a.m.  Approximately 50 degrees F)

October 27, 2019   (11:57 a.m.  Approximately 45 degrees F)

November 1, 2019   (9:31 a.m.   Approximately 35 degrees F)

November 4, 2019   (10:22 a.m.   Approximately 45 degrees F)

November 8, 2019   (10:07 a.m.   Approximately 25 degrees F)

November 13, 2019   (10:52 a.m.   Approximately 15 degrees)

The changes from the middle of October to the middle of November, always dramatic along the river in Eliza Howell Park, were even more dramatic this year because of the unusually heavy snow of November 11.

 

A Sunny Morning in Late October

The early morning sun was shining and there was a combination of dew and frost on the ground when I arrived at Detroit’s Eliza Howell Park on October 28, 2019. Here are a few images from the next three hours.

Bittersweet on Oak Tree

Bittersweet vines grow high on some trees in the park, most noticeable when the leaves of the vine turn yellow.

Dew Drop on Sumac

In the blow up, one can clearly see the reflections.

Three Hundred Year Old Bur Oak Tree

I stopped by a massive Bur Oak that has been estimated to be over 300 years old.

Rouge River from Footbridge

I often take a picture from this spot, looking upstream. The look of the river changes with the season, the sunlight/clouds, and the water level.

A Walk in the Woods

Sugar Maple

Several Sugar Maple trees, seen from the park road, have inspired park visitors to pull out their cameras.

A Favorite Cottonwood

There are some trees, friends, that I stop by to visit to see how they are doing. This Cottonwood tree is one.

In my records, this is Walk # 1351. Another good one.

 

Bitternut Hickory: Searching for a Better Name

I was standing under a Bitternut Hickory tree the other day in Eliza Howell Park when a falling nut hit me on the head. It wasn’t quite an “aha moment” – as in the story of Newton, the falling apple, and gravity – but it somehow reinforced my intent to find a better name for this tree.

In October, Carya cordiformis, the tree usually known as “Bitternut Hickory,” gets my attention for a stately golden beauty.

It is not unusual for the common name of a tree species to be based on the appearance or characteristic or use of the tree or its fruit – for example, Shagbark Hickory, Black Cherry, Kentucky Coffee Tree. That seems different, though, from a name that is based on a judgment of the tastiness of the fruit.

Tastes vary, but the name suggest that no one will like the fruit, with the possible result that people will not even pick up a few for their own taste test.

Deciding that I preferred a name that is more descriptive of the plant and less a commentary on the quality of the nut as food, I began to look for possibilities. The “cordiformis” in the scientific name means “heart shaped.” This refers, I would think, to the shape of the nut. I don’t know if that would be a good common name, but I have not  seen that name used in English.

As a tree and as a fruit, “Bitternut Hickory” is often compared with Shagbark Hickory. The common name Shagbark is, of course, based on the bark. The bark of “Bitternut” is smoother than that Shagbark, but there is little about the bark that suggests a name – and I have not seen any attempts at such naming. In the picture, Shagbark is on the left, “Bitternut” on the right.

Based on what I have been seeing this month, my personal preference for the name would be something like “Golden Hickory.”

Unfortunately, this name does not appear in any of the articles or reports on the species.

Another characteristic of the species – and one I often use for identification – is that the husk of the nut has four narrow ridges that extend down from the outer tip.

“Ridged Hickory” might be acceptable name, but I have not been able to find anyone calling it that.

There are two English names besides “Bitternut” that are sometimes used in the published accounts: “Yellow Bud Hickory” and “Swamp Hickory.” “Swamp” seems to me to more misleading than helpful; the tree is found in many locations that are not swamp.

“Yellow Bud” is based on the fact that the winter bud is yellowish, a distinguishing characteristic. I confess that I have not paid particular attention to this fact and do not have a single picture of the bud. However, the name is based on an identifying characteristic of the species and has been used enough that searching under this name will bring up the right information.

A picture of a Yellow Bud Hickory in Eliza Howell in October:

I think my search for an alternative name to “Bitternut” may be over. I plan to use “Yellow Bud” from now on. And this winter I will pay attention to the buds.